''The idea is to stop and think about how badly you need light before you use it.''

Umm, we need light pretty badly. We have a surplus of energy (in the West) and without artificial light our civilisation would not be where it is at today. If anything, the materials used to create this ''blood'' lamp are pretty wasteful in itself, especially since the message of it will be wasted.

erm, i think the point IS that we have a surplus. We take it for granted because we can just flip a switch. So adding the blood makes you stop and say to yourself, "hmm, im willing to cut myself and offer my blood for a little bit of light? Imagine how hard life must be for those who do not have this access." Then the message IS getting across.